1. Field of the Invention
This invention relates generally to data reproduction systems, and relates more particularly to an apparatus and method for implementing a variable-speed audio data playback system.
2. Description of the Background Art
Implementing an effective and efficient method for the playback of audio data is a significant consideration of designers, manufacturers, and users of contemporary audio systems. Modem audio playback systems are typically required to accurately reproduce various types of audio data. For example, a digital video-disc device may be utilized to reproduce recordings of motion picture soundtracks that include various combinations of voice, music and background sounds. Current advances in digital audio technology have further increased the importance of preserving high sound quality in any audio playback system.
One special playback technique that may be advantageously used in many audio devices is a variable-speed playback function. For example, a system user may wish to use a program search mode to rapidly shuttle forward at double the normal playback speed in order to quickly locate a particular remote point in the recorded program. To facilitate locating the desired point in the recorded program, the system user typically aurally monitors the audio playback during variable-speed playback mode. The playback sound quality that is available during the variable-speed playback mode is therefore a significant performance factor that can enhance the efficiency and user-friendliness of such an audio reproduction system.
Some audio reproduction systems include variable-speed playback modes that simply provide the audio data to the listener at a higher rate of speed. For example, if such a system featured a double-speed playback mode, then the reproduced audio program would be played back at twice the originally-recorded speed, and the pitch of the audio program would be similarly doubled. This rapid playback speed and the corresponding distorted audio program result in substantially decreased performance for the system user.
Other audio reproduction systems feature variable-speed playback modes that produce the audio program with various types of sound artifacts. For example, some of the sound artifacts present in selected variable-speed audio devices include clicking-type sounds and warbling sound distortion. In spite of the difficulties encountered, variable-speed playback functionality remains a beneficial and important feature for enhanced operation of contemporary audio playback systems. Therefore, for all the foregoing reasons, an improved method is needed for implementing a variable-speed audio data playback system.